In vitro evaluation of five rapid antigen detection tests for group A beta-haemolytic streptococcal sore throat infections

Objective. The purpose of this study was to evaluate the ease of use and in vitro accuracy (sensitivity and specificity) of the five most commonly used RADTs in Europe (OSOM Ultra, Quickvue Dipstick, Streptatest, Clearview Exact Strep A and IMI Test Pack). Methods. To ensure the RADTs were evaluated objectively, a standardized in vitro method using known concentrations of GABHS was used to remove the inherent biases associated with clinical studies. Results. The IMI Test Pack was the easiest RADT to use overall. The ability to detect all positive GABHS (sensitivity) varied considerably between kits from 95% [95% confidence interval (CI): 88-98%], for the IMI Test Pack and OSOM, to 62% (95% CI: 51-72%) for Clearview, at the highest GABHS concentration. None of the RADTs gave any false-positive results with commensal flora-they were 100% specific. Conclusions. The IMI Test Pack is most suitable for use in primary care, as it had high sensitivity, high specificity and was easy to use.